This invention relates to a high-frequency treatment device to be pierced into a guide channel of an endoscope.
FIG. 2 of Japanese Patent Application Laid-Open No. 59526/1982 discloses a mono-polar type high-frequency treatment device. FIG. 3 of this publication discloses a bipolar type high-frequency treatment device. In this mono-polar type high-frequency treatment device, a single electrode is disposed within a distal end of an elongated tubular piercing portion. In the bipolar type high-frequency treatment device, a pair of rod-like electrodes are arranged within the distal end of the piercing portion in a spaced and parallel relation.
In the high-frequency treatment device thus constructed, the piercing portion is pierced into the guide channel of the endoscope and a high-frequency current is supplied to the tissue of an organic body through one or two electrodes, with the distal end of the piercing portion projecting from a distal end of the endoscope, to thereby make a treatment to the tissue of the organic body (chiefly, coagulation of the tissue).
Incidentally, in the field of brain surgery or the like, a bipolar type high-frequency treatment device is used because it can supply a high-frequency current to a limited area of the nerve tissue to diminish any adverse effect to the nerve tissue. In this field, there are strong demands for an endoscope to have a more reduced diameter. As this demand is increased, the treatment device to be pierced into the guide channel of the endoscope is increasingly required to have a smaller diameter. However, in the high-frequency treatment device having a pair of parallel bar-like electrodes as mentioned above, it is difficult to reduce the diameter. Moreover, such an arrangement of the electrodes results in a complicated construction.